Oak tree named &#39;Adeline&#39;

ABSTRACT

A new and distinct Hybrid Oak named ‘Adeline’ characterized by its very narrow pyramidal habit of growth, its winter hardiness, and hybrid vigor. Also for its beautiful dark green, mildew-resistant foliage and its ability to withstand wind and ice without breakage.

The present invention comprises a new and distinct cultivar of a F₁ hybrid oak tree, botanically known as Quercus bicolor×Quercus robur var. fastigiata or the Ware oak Quercus×warei and referred to by the cultivar name ‘Adeline’. The parent tree is growing in a cultivated area at the home of William Walkenbach, 1820 Hwy. West, Hermann, Mo. 65041, in Gasconade County, Township 45 North, Range 5 West, Section 16. The new cultivar ‘Adeline’ is the result of seed collected in the fall of 1990 from a swamp white oak (Quercus bicolor) tree.

The ‘Adeline’ cultivar is an extremely narrow-upright pyramidal form (FIG. 1) that keeps a narrow pyramidal form from its base to its top. It is very strong wooded tree with dark green leathery foliage (FIG. 4) that is highly resistant to powdery mildew. Its parentage would indicate it to be hardy in Zone 4 b and possibly 4a, (U.S.D.A. Hardiness Zone Map). The new ‘Adeline’ cultivar has been successfully asexually propagated by chip budding onto Quercus bicolor. Bud take has been near 95% with no incompatibility between scion and rootstock.

Buds set on two year rootstocks have produced five to six feet (152.4-182.9 cm) of growth in one growing season. Asexually propagated trees of the ‘Adeline’ cultivar have maintained their unique characteristics which, in combination, distinguish this cultivar selection from both of its parents, Quercus bicolor and Quercus robur var. fastigiata (FIG. 3).

1. The ‘Adeline’ oak tree at 15 years of age is 25 feet (7.6m) in height, with a total limb spread of seven feet (2.1 m). The narrow form of the ‘Adeline’ oak tree could be used in several different ways in the landscape. It can be planted on city streets where a very limited space exists. It could also be planted to form a narrow screen or windbreak. It would lend itself well in a landscape planting where repetition of a narrow pyramidal form would be desired or it could be planted in a park or on a golf course as a specimen tree.

2. The ‘Adeline’ oak is highly resistant to wind and ice. It has never suffered any breakage from either wind or ice. Its pistillate parent, Quercus bicolor, would account for the resilience of its wood during storms. The species Quercus bicolor is known for having wood of great strength.

3. Foliage of the ‘Adeline’ hybrid oak tree is dark green on the upper surface and silvery light green on the under-surface (FIG. 4). This tree has also proven to be highly resistant to powdery mildew.

4. Compared to Quercus robur var. fastigiata, this new hybrid is far more winter hardy.

5. The ‘Adeline’ oak exhibits remarkable hybrid vigor. A chip bud set on a two-year old Quercus bicolor seedling will make five to six feet of growth in one growing season.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The Royal Horticultural Society Colour Chart.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying colored photographs illustrate the appearance and color of the new oak tree. These photographs show the color as accurately as is reasonably possible to obtain in colored reproductions of this type. Actual foliage colors may differ slightly due to light reflectance.

FIG. 1 depicts the initially discovered tree named in summer foliage showing its very narrow form.

FIG. 2 depicts the oak tree without foliage.

FIG. 3 depicts the first asexually propagated (chip budded) tree of the cultivar.

FIG. 4 depicts the mature acorn and peduncle of the oak in late autumn.

FIG. 5 depicts the foliage of the ‘Adeline’ cultivar, upper surface of the leaf shows no evidence of powdery mildew.

FIG. 6 depicts the stem, including terminal and lateral buds.

THE PLANT

TREE, HYBRID OAK ‘Adeline’

-   Name: cultivar ‘Adeline’ -   Parentage: Seedling or Sport: Seedling, 1991 Seed parent Quercus     bicolor Pollen parent Quercus robur var. fastigiata.     -   -   Classification.—Quercus×warei.         -   Botanic name.—Quercus robur var. fastigiata×Quercus bicolor,             hybrid. oak.         -   Discovered.—In a cultivated area, at the home of William             Walkenbach, 1820 Hwy. West, Hermann, Mo. 65041, Gasconade             County, Township 45 North, Range 5 West, Section 16. This             plant has been asexually reproduced by grafting (chip             budding) onto Swamp White Oak Quercus bicolor seedling             rootstock. Presently, propagation is being performed at             three different nurseries with one nursery in each of the             following states Ill., Mo., and Oreg.         -   Form.—Tree.         -   Shape.—narrow pyramidal.         -   Height.—7.62 m (25′); Spread 2.13 m (7′).         -   Trunk size (diameter of trunk at 137 cm above ground             level).—9.53 cm (3.75″).         -   Base.—cylindrical.         -   Growth rate.—Excellent, with robust hybrid vigor.         -   Strength.—Excellent.         -   Age.—15 years from a planted acorn.         -   Bark (trunk).—Bark dark grey to light grey (197A&B); small             rectangular blocks with vertical furrows; medium-course in             texture, size of blocks are 1.9-2.54 cm (0.75-1.0″) wide,             3.81-6.35 cm (1.5-2.5″) long. -   Branches:     -   -   Angle of attachment.—lower branches between 30° and 60° with             the upper portion of the tree at 20° to 30°.         -   Spacing.—Dense Small twig bark: (<0.7 cm diameter) (growing             season) greenish, smooth (195A) (dormant season) grey-green             (197A) and grey-purple (183A).         -   Lenticels.—small (μ=0.4 mm) on branches less than 6 mm in             diameter, scattered, round, raised, color (196C).         -   Small branch bark.—(0.7-2.5 cm diameter) gray (198A) mottled             with brown (199B), smooth, exfoliation begins at 1.3 cm in             diameter. -   Leaves: -   Petiole:     -   -   Length.—(0.3-1.0 cm, μ=0.59 cm).         -   Color.—green (144B&C).         -   Texture.—smooth. -   Lamina:     -   -   Length.—5.08-14.9 cm, (μ=11.6 cm).         -   Width.—3.0-8.6 cm, (μ=6.6 cm).         -   Form.—Lamina: obovate; base cuneate to acute narrowly             cordate on some leaves; apex obtuse to broadly acute.         -   Margin.—shallowly lobed with 6-8 pairs of obtuse teeth.         -   Texture.—Membranous, leathery, glossy, smooth, glabrous             above, and pubescent on underside.         -   Quantity.—abundant.         -   Color.—Upper side: (summer) dark green (139A) (autumnal)             color changes from shades of yellow-green (152A, 153A,&154A)             to brown (199A)) Lower side: leaves are grayish green (193A)             Ribs and veins.—6-8 pairs of lobes with 10-12 pairs of             veins; greenish-yellow (151B); pinnate pattern of venation. -   Buds: (Vegetative) Small triangular in shape (0.16-0.5 cm) μ=0.3 cm,     gray-orange, (176A) and brown (199D) covered with an imbricate     pattern of scales. -   Flowers: Imperfect, monoecious; staminate aments are pendent,     clustered, length cm (μ=6.0 cm) color of aments, yellow-green (150A)     to yellow-green (150C); pistillate flowers found in axils of     emerging new leaves, ovary surrounded by a calyx which is enclosed     in a cupule, 0.8 mm in length, yellow-green in color (150C). -   Fruit: On peduncle (1.3-4.6 cm), μ=2.5 cm long, mostly solitary or     with undeveloped second fruit; cap gray-brown (199D) with warty     scales; cap measures (1.8-2.5) cm with μ=2.4 cm wide by (1.3-1.8) cm     with (μ=1.4 cm) long; nut gray-orange 166 A, 165 A and B ( 2.3-2.8 )     cm, μ=2.5 cm long by (1.4-2.0) cm, 9 μ=1.7 cm) wide, apex sharp     point (0.6-1.6 mm), (μ=1.2 mm) long; ovoid; cap encloses nut     (40-60%), μ=50%. -   Has this plant ever been offered for sale?: No. -   Compare this new variety: with others of the same species and with     its parent or parents; state the distinguishing characteristics of     the new cultivar and its advantages. This tree is an extremely     narrow-pyramidal form. It is similar to the oak cultivars ‘Nadler’     and ‘Long’ in leaf appearance, bark character, and fruit size, but     differs in having a very narrow pyramidal shape in contrast to the     narrow fastigate form of the ‘Nadler oak and the medium-oval form of     the ‘Long’ oak. Swamp white oak (Quercus bicolor) the female parent     of the ‘Adeline’ oak tree develops a broad open round-topped crown     and a short trunk in contrast to the narrow-pyramidal form of the     ‘Adeline’ cultivar. The ‘Adeline’ oak differs from the form of its     staminate parent, Quercus robur var. fastigata, by having a very     narrow-pyramidal form instead of a fastigate habit of growth. It     also differs from Quercus robur var. fastigata by having     mildew-resistant dark, shiny green leaves with a silvery-white     underside. It has bold, dark green, mildew-resistant foliage with     highly ornamental silvery lower surfaces similar to its seed parent.     This tree's genetic heritage has made it winter hardy, adaptable to     almost any soil, and tolerant of drought and flooding. 

1. A new and distinct cultivar of hybrid oak Quercus bicolor×Quercus robur var. fastigiata, named ‘Adeline’, as illustrated and described. 